Pepper: Move FileIO host from renderer to browser.

content/browser/renderer_host/pepper/pepper_file_io_host.cc

Index: content/browser/renderer_host/pepper/pepper_file_io_host.cc
diff --git a/content/browser/renderer_host/pepper/pepper_file_io_host.cc b/content/browser/renderer_host/pepper/pepper_file_io_host.cc
new file mode 100644
index 0000000000000000000000000000000000000000..3f6681fad7c0495ad4a8c84e039e42a653a768df
--- /dev/null
+++ b/content/browser/renderer_host/pepper/pepper_file_io_host.cc
@@ -0,0 +1,545 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "content/browser/renderer_host/pepper/pepper_file_io_host.h"
+
+#include "base/bind.h"
+#include "base/callback.h"
+#include "base/callback_helpers.h"
+#include "base/command_line.h"
+#include "base/files/file_util_proxy.h"
+#include "base/memory/weak_ptr.h"
+#include "content/browser/renderer_host/pepper/pepper_file_ref_host.h"
+#include "content/browser/renderer_host/pepper/pepper_security_helper.h"
+#include "content/browser/renderer_host/pepper/quota_file_io.h"
+#include "content/common/fileapi/file_system_messages.h"
+#include "content/common/sandbox_util.h"
+#include "content/common/view_messages.h"
+#include "content/public/browser/browser_thread.h"
+#include "content/public/browser/content_browser_client.h"
+#include "content/public/browser/render_process_host.h"
+#include "content/public/browser/storage_partition.h"
+#include "content/public/common/content_client.h"
+#include "ppapi/c/pp_errors.h"
+#include "ppapi/c/ppb_file_io.h"
+#include "ppapi/host/dispatch_host_message.h"
+#include "ppapi/host/ppapi_host.h"
+#include "ppapi/proxy/ppapi_messages.h"
+#include "ppapi/shared_impl/file_type_conversion.h"
+#include "ppapi/shared_impl/time_conversion.h"
+#include "webkit/browser/fileapi/file_observers.h"
+#include "webkit/browser/fileapi/file_system_context.h"
+#include "webkit/browser/fileapi/task_runner_bound_observer_list.h"
+#include "webkit/browser/quota/quota_manager.h"
+#include "webkit/common/fileapi/file_system_util.h"
+
+namespace content {
+
+using ppapi::FileIOStateManager;
+using ppapi::PPTimeToTime;
+
+namespace {
+
+int32_t ErrorOrByteNumber(int32_t pp_error, int32_t byte_number) {
+  // On the plugin side, some callbacks expect a parameter that means different
+  // things depending on whether is negative or not.  We translate for those

[bbudge, 2013/10/22 01:59:39]

s/is/it is

[teravest, 2013/10/22 15:45:05]

Done.

+  // callbacks here.
+  return pp_error == PP_OK ? byte_number : pp_error;
+}
+
+class QuotaFileIODelegate : public QuotaFileIO::Delegate {
+ public:
+  QuotaFileIODelegate(scoped_refptr<fileapi::FileSystemContext> context,
+                      int render_process_id)
+      : context_(context),
+        weak_factory_(this) { }
+  virtual ~QuotaFileIODelegate() {}
+
+  virtual void QueryAvailableSpace(
+      const GURL& origin,
+      quota::StorageType type,
+      const AvailableSpaceCallback& callback) OVERRIDE {
+    DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+    quota::QuotaManagerProxy* quota_manager_proxy =
+        context_->quota_manager_proxy();
+    DCHECK(quota_manager_proxy);
+    if (!quota_manager_proxy) {
+      callback.Run(0);
+      return;
+    }
+    quota::QuotaManager* qm = quota_manager_proxy->quota_manager();
+    DCHECK(qm);
+    if (!qm) {
+      callback.Run(0);
+      return;
+    }
+    qm->GetUsageAndQuotaForWebApps(
+        origin,
+        type,
+        base::Bind(&QuotaFileIODelegate::GotUsageAndQuotaForWebApps,
+            weak_factory_.GetWeakPtr(), callback));
+  }
+
+  void GotUsageAndQuotaForWebApps(const AvailableSpaceCallback& callback,
+                                  quota::QuotaStatusCode code,
+                                  int64 usage,
+                                  int64 quota) {
+    if (code == quota::kQuotaStatusOk)
+      callback.Run(std::max(static_cast<int64>(0), quota - usage));
+    else
+      callback.Run(0);
+  }
+
+  virtual void WillUpdateFile(const GURL& file_path) OVERRIDE {
+    DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+    fileapi::FileSystemURL url(context_->CrackURL(file_path));
+    if (!url.is_valid())
+      return;
+    const fileapi::UpdateObserverList* observers =
+        context_->GetUpdateObservers(url.type());
+    if (!observers)
+      return;
+    observers->Notify(&fileapi::FileUpdateObserver::OnStartUpdate,
+                      MakeTuple(url));
+  }
+  virtual void DidUpdateFile(const GURL& file_path, int64_t delta) OVERRIDE {
+    DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+    fileapi::FileSystemURL url(context_->CrackURL(file_path));
+    if (!url.is_valid())
+      return;
+    const fileapi::UpdateObserverList* observers =
+        context_->GetUpdateObservers(url.type());
+    if (!observers)
+      return;
+    observers->Notify(&fileapi::FileUpdateObserver::OnUpdate,
+                      MakeTuple(url, delta));
+    observers->Notify(&fileapi::FileUpdateObserver::OnEndUpdate,
+                      MakeTuple(url));
+  }
+  virtual scoped_refptr<base::MessageLoopProxy>
+      GetFileThreadMessageLoopProxy() OVERRIDE {
+    return BrowserThread::GetMessageLoopProxyForThread(BrowserThread::FILE);
+  }
+ private:
+  scoped_refptr<fileapi::FileSystemContext> context_;
+  base::WeakPtrFactory<QuotaFileIODelegate> weak_factory_;
+};
+
+// TODO(teravest): Don't duplicate code with PepperFileSystemBrowserHost.
+scoped_refptr<fileapi::FileSystemContext>
+GetFileSystemContextFromRenderId(int render_process_id) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  RenderProcessHost* render_process_host =
+      RenderProcessHost::FromID(render_process_id);
+  if (!render_process_host)
+    return NULL;
+  StoragePartition* storage_partition =
+      render_process_host->GetStoragePartition();
+  if (!storage_partition)
+    return NULL;
+  return storage_partition->GetFileSystemContext();
+}
+
+}  // namespace
+
+PepperFileIOHost::PepperFileIOHost(BrowserPpapiHostImpl* host,
+                                   PP_Instance instance,
+                                   PP_Resource resource)
+    : ResourceHost(host->GetPpapiHost(), instance, resource),
+      browser_ppapi_host_(host),
+      render_process_host_(NULL),
+      file_(base::kInvalidPlatformFileValue),
+      file_system_type_(PP_FILESYSTEMTYPE_INVALID),
+      quota_policy_(quota::kQuotaLimitTypeUnknown),
+      open_flags_(0),
+      weak_factory_(this) {
+  int unused;
+  if (!host->GetRenderViewIDsForInstance(instance,
+                                         &render_process_id_,
+                                         &unused)) {
+    render_process_id_ = -1;
+  }
+  file_message_loop_ = BrowserThread::GetMessageLoopProxyForThread(
+      BrowserThread::FILE);
+}
+
+PepperFileIOHost::~PepperFileIOHost() {
+  OnHostMsgClose(NULL);
+}
+
+int32_t PepperFileIOHost::OnResourceMessageReceived(
+    const IPC::Message& msg,
+    ppapi::host::HostMessageContext* context) {
+  IPC_BEGIN_MESSAGE_MAP(PepperFileIOHost, msg)
+    PPAPI_DISPATCH_HOST_RESOURCE_CALL(PpapiHostMsg_FileIO_Open,
+                                      OnHostMsgOpen)
+    PPAPI_DISPATCH_HOST_RESOURCE_CALL(PpapiHostMsg_FileIO_Touch,
+                                      OnHostMsgTouch)
+    PPAPI_DISPATCH_HOST_RESOURCE_CALL(PpapiHostMsg_FileIO_Write,
+                                      OnHostMsgWrite)
+    PPAPI_DISPATCH_HOST_RESOURCE_CALL(PpapiHostMsg_FileIO_SetLength,
+                                      OnHostMsgSetLength)
+    PPAPI_DISPATCH_HOST_RESOURCE_CALL_0(PpapiHostMsg_FileIO_Flush,
+                                        OnHostMsgFlush)
+    PPAPI_DISPATCH_HOST_RESOURCE_CALL_0(PpapiHostMsg_FileIO_Close,
+                                        OnHostMsgClose)
+    PPAPI_DISPATCH_HOST_RESOURCE_CALL_0(PpapiHostMsg_FileIO_RequestOSFileHandle,
+                                        OnHostMsgRequestOSFileHandle)
+  IPC_END_MESSAGE_MAP()
+  return PP_ERROR_FAILED;
+}
+
+int32_t PepperFileIOHost::OnHostMsgOpen(
+    ppapi::host::HostMessageContext* context,
+    PP_Resource file_ref_resource,
+    int32_t open_flags) {
+  int32_t rv = state_manager_.CheckOperationState(
+      FileIOStateManager::OPERATION_EXCLUSIVE, false);
+  if (rv != PP_OK)
+    return rv;
+
+  int platform_file_flags = 0;
+  if (!ppapi::PepperFileOpenFlagsToPlatformFileFlags(open_flags,
+                                                     &platform_file_flags))
+    return PP_ERROR_BADARGUMENT;
+
+  ppapi::host::ResourceHost* resource_host =
+      host()->GetResourceHost(file_ref_resource);
+  if (!resource_host || !resource_host->IsFileRefHost())
+    return PP_ERROR_BADRESOURCE;
+  PepperFileRefHost* file_ref_host =
+      static_cast<PepperFileRefHost*>(resource_host);
+  if (file_ref_host->GetFileSystemType() == PP_FILESYSTEMTYPE_INVALID)
+    return PP_ERROR_FAILED;
+
+  open_flags_ = open_flags;
+  file_system_type_ = file_ref_host->GetFileSystemType();
+  file_system_url_ = file_ref_host->GetFileSystemURL();
+
+  if (file_system_type_ != PP_FILESYSTEMTYPE_EXTERNAL) {
+    DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+    fileapi::FileSystemURL url(file_ref_host->GetFileSystemURL());
+    if (!url.is_valid())
+      return PP_ERROR_BADARGUMENT;
+    if (!CanOpenFileSystemURLWithPepperFlags(open_flags,
+                                             render_process_id_,
+                                             url))
+      return PP_ERROR_NOACCESS;
+
+    BrowserThread::PostTaskAndReplyWithResult(
+        BrowserThread::UI,
+        FROM_HERE,
+        base::Bind(&GetFileSystemContextFromRenderId, render_process_id_),
+        base::Bind(&PepperFileIOHost::GotFileSystemContext,
+                   weak_factory_.GetWeakPtr(),
+                   context->MakeReplyMessageContext(),
+                   platform_file_flags));
+  } else {
+    base::FilePath path = file_ref_host->GetExternalFilePath();
+    if (!CanOpenWithPepperFlags(open_flags, render_process_id_, path))
+      return PP_ERROR_NOACCESS;
+    base::FileUtilProxy::CreateOrOpen(
+        file_message_loop_,
+        path,
+        platform_file_flags,
+        base::Bind(&PepperFileIOHost::ExecutePlatformOpenFileCallback,
+                   weak_factory_.GetWeakPtr(),
+                   context->MakeReplyMessageContext()));
+  }
+  state_manager_.SetPendingOperation(FileIOStateManager::OPERATION_EXCLUSIVE);
+  return PP_OK_COMPLETIONPENDING;
+}
+
+void PepperFileIOHost::GotFileSystemContext(
+    ppapi::host::ReplyMessageContext reply_context,
+    int platform_file_flags,
+    scoped_refptr<fileapi::FileSystemContext> file_system_context) {
+  if (!file_system_context.get()) {
+    reply_context.params.set_result(PP_ERROR_FAILED);
+    host()->SendReply(reply_context, PpapiPluginMsg_FileIO_OpenReply());
+    return;
+  }
+  file_system_context_ = file_system_context;
+
+  if (file_system_context_->GetFileSystemBackend(
+          file_system_url_.type()) == NULL) {

[bbudge, 2013/10/22 01:59:39]

nit: !expr seems more consistent with the rest of the file than "== NULL".

[teravest, 2013/10/22 15:45:05]

Done.

+    reply_context.params.set_result(PP_ERROR_FAILED);
+    host()->SendReply(reply_context, PpapiPluginMsg_FileIO_OpenReply());
+    return;
+  }
+  quota_policy_ = quota::kQuotaLimitTypeUnknown;
+  quota::QuotaManagerProxy* quota_manager_proxy =
+      file_system_context_->quota_manager_proxy();
+  CHECK(quota_manager_proxy);
+  CHECK(quota_manager_proxy->quota_manager());
+  if (quota_manager_proxy->quota_manager()->IsStorageUnlimited(
+          file_system_url_.origin(),
+          fileapi::FileSystemTypeToQuotaStorageType(file_system_url_.type())))
+    quota_policy_ = quota::kQuotaLimitTypeUnlimited;
+  else
+    quota_policy_ = quota::kQuotaLimitTypeLimited;
+  file_system_operation_runner_ =
+      file_system_context_->CreateFileSystemOperationRunner();
+  file_system_operation_runner_->OpenFile(
+      file_system_url_,
+      platform_file_flags,
+      browser_ppapi_host_->GetPluginProcessHandle(),
+      base::Bind(&PepperFileIOHost::DidOpenFile,
+          weak_factory_.GetWeakPtr(),

[bbudge, 2013/10/22 01:59:39]

nit: Indent is different from other base::Bind invocations in the file.

[teravest, 2013/10/22 15:45:05]

Done.

+          reply_context));
+}
+
+void PepperFileIOHost::DidOpenFile(
+    ppapi::host::ReplyMessageContext reply_context,
+    base::PlatformFileError result,
+    base::PlatformFile file,
+    const base::Closure& on_close_callback,
+    base::ProcessHandle peer_handle) {
+  if (result == base::PLATFORM_FILE_OK)
+    on_close_callback_ = on_close_callback;
+  ExecutePlatformOpenFileCallback(
+      reply_context, result, base::PassPlatformFile(&file), true);
+}
+
+int32_t PepperFileIOHost::OnHostMsgTouch(
+    ppapi::host::HostMessageContext* context,
+    PP_Time last_access_time,
+    PP_Time last_modified_time) {
+  int32_t rv = state_manager_.CheckOperationState(
+      FileIOStateManager::OPERATION_EXCLUSIVE, true);
+  if (rv != PP_OK)
+    return rv;
+
+  if (!base::FileUtilProxy::Touch(
+          file_message_loop_,
+          file_,
+          PPTimeToTime(last_access_time),
+          PPTimeToTime(last_modified_time),
+          base::Bind(&PepperFileIOHost::ExecutePlatformGeneralCallback,
+                     weak_factory_.GetWeakPtr(),
+                     context->MakeReplyMessageContext())))
+    return PP_ERROR_FAILED;
+
+  state_manager_.SetPendingOperation(FileIOStateManager::OPERATION_EXCLUSIVE);
+  return PP_OK_COMPLETIONPENDING;
+}
+
+int32_t PepperFileIOHost::OnHostMsgWrite(
+    ppapi::host::HostMessageContext* context,
+    int64_t offset,
+    const std::string& buffer) {
+  int32_t rv = state_manager_.CheckOperationState(
+      FileIOStateManager::OPERATION_WRITE, true);
+  if (rv != PP_OK)
+    return rv;
+
+  if (quota_file_io_) {
+    if (!quota_file_io_->Write(
+            offset, buffer.c_str(), buffer.size(),
+            base::Bind(&PepperFileIOHost::ExecutePlatformWriteCallback,
+                       weak_factory_.GetWeakPtr(),
+                       context->MakeReplyMessageContext())))
+      return PP_ERROR_FAILED;
+  } else {
+    if (!base::FileUtilProxy::Write(
+            file_message_loop_,
+            file_,
+            offset,
+            buffer.c_str(),
+            buffer.size(),
+            base::Bind(&PepperFileIOHost::ExecutePlatformWriteCallback,
+                       weak_factory_.GetWeakPtr(),
+                       context->MakeReplyMessageContext())))
+      return PP_ERROR_FAILED;
+  }
+
+  state_manager_.SetPendingOperation(FileIOStateManager::OPERATION_WRITE);
+  return PP_OK_COMPLETIONPENDING;
+}
+
+int32_t PepperFileIOHost::OnHostMsgSetLength(
+    ppapi::host::HostMessageContext* context,
+    int64_t length) {
+  int32_t rv = state_manager_.CheckOperationState(
+      FileIOStateManager::OPERATION_EXCLUSIVE, true);
+  if (rv != PP_OK)
+    return rv;
+
+  QuotaFileIO::StatusCallback cb =
+      base::Bind(&PepperFileIOHost::ExecutePlatformGeneralCallback,
+                 weak_factory_.GetWeakPtr(),
+                 context->MakeReplyMessageContext());
+  if (quota_file_io_) {
+    if (!quota_file_io_->SetLength(length, cb))
+      return PP_ERROR_FAILED;
+  } else {
+    if (!base::FileUtilProxy::Truncate(file_message_loop_, file_, length, cb))
+      return PP_ERROR_FAILED;
+  }
+
+  state_manager_.SetPendingOperation(FileIOStateManager::OPERATION_EXCLUSIVE);
+  return PP_OK_COMPLETIONPENDING;
+}
+
+int32_t PepperFileIOHost::OnHostMsgFlush(
+    ppapi::host::HostMessageContext* context) {
+  int32_t rv = state_manager_.CheckOperationState(
+      FileIOStateManager::OPERATION_EXCLUSIVE, true);
+  if (rv != PP_OK)
+    return rv;
+
+  if (!base::FileUtilProxy::Flush(
+          file_message_loop_,
+          file_,
+          base::Bind(&PepperFileIOHost::ExecutePlatformGeneralCallback,
+                     weak_factory_.GetWeakPtr(),
+                     context->MakeReplyMessageContext())))
+    return PP_ERROR_FAILED;
+
+  state_manager_.SetPendingOperation(FileIOStateManager::OPERATION_EXCLUSIVE);
+  return PP_OK_COMPLETIONPENDING;
+}
+
+int32_t PepperFileIOHost::OnHostMsgClose(
+    ppapi::host::HostMessageContext* context) {
+  if (file_ != base::kInvalidPlatformFileValue) {
+    base::FileUtilProxy::Close(
+        file_message_loop_,
+        file_,
+        base::ResetAndReturn(&notify_close_file_callback_));
+    file_ = base::kInvalidPlatformFileValue;
+    quota_file_io_.reset();
+  }
+  return PP_OK;
+}
+
+int32_t PepperFileIOHost::OnHostMsgRequestOSFileHandle(
+    ppapi::host::HostMessageContext* context) {
+  if (open_flags_ != PP_FILEOPENFLAG_READ &&
+      quota_policy_ != quota::kQuotaLimitTypeUnlimited)
+    return PP_ERROR_FAILED;
+  GetRenderProcessHost(
+      base::Bind(&PepperFileIOHost::FinishRequestOSFileHandle,
+                 weak_factory_.GetWeakPtr(),
+                 context->MakeReplyMessageContext()));
+  return PP_OK_COMPLETIONPENDING;
+}
+
+void PepperFileIOHost::FinishRequestOSFileHandle(
+    ppapi::host::ReplyMessageContext reply_context,
+    RenderProcessHost* render_process_host) {
+  // Whitelist to make it privately accessible.
+  if (!browser_ppapi_host_->external_plugin() ||
+      host()->permissions().HasPermission(ppapi::PERMISSION_PRIVATE) ||
+      GetContentClient()->browser()->IsPluginAllowedToCallRequestOSFileHandle(
+          render_process_host->GetBrowserContext(),
+          browser_ppapi_host_->GetDocumentURLForInstance(pp_instance()))) {
+    if (!AddFileToReplyContext(open_flags_, &reply_context))
+      reply_context.params.set_result(PP_ERROR_FAILED);
+  } else {
+    reply_context.params.set_result(PP_ERROR_NOACCESS);
+  }
+  host()->SendReply(reply_context,
+                    PpapiPluginMsg_FileIO_RequestOSFileHandleReply());
+}
+
+void PepperFileIOHost::ExecutePlatformGeneralCallback(
+    ppapi::host::ReplyMessageContext reply_context,
+    base::PlatformFileError error_code) {
+  reply_context.params.set_result(
+      ppapi::PlatformFileErrorToPepperError(error_code));
+  host()->SendReply(reply_context, PpapiPluginMsg_FileIO_GeneralReply());
+  state_manager_.SetOperationFinished();
+}
+
+void PepperFileIOHost::ExecutePlatformOpenFileCallback(
+    ppapi::host::ReplyMessageContext reply_context,
+    base::PlatformFileError error_code,
+    base::PassPlatformFile file,
+    bool unused_created) {
+  int32_t pp_error = ppapi::PlatformFileErrorToPepperError(error_code);
+  if (pp_error == PP_OK)
+    state_manager_.SetOpenSucceed();
+
+  DCHECK(file_ == base::kInvalidPlatformFileValue);
+  file_ = file.ReleaseValue();
+
+  DCHECK(!quota_file_io_.get());
+  if (file_ != base::kInvalidPlatformFileValue) {
+    if (file_system_type_ == PP_FILESYSTEMTYPE_LOCALTEMPORARY ||
+        file_system_type_ == PP_FILESYSTEMTYPE_LOCALPERSISTENT) {
+      quota_file_io_.reset(new QuotaFileIO(
+          new QuotaFileIODelegate(file_system_context_, render_process_id_),
+              file_, file_system_url_.ToGURL(), file_system_type_));
+    }
+    int32_t flags_to_send = open_flags_;
+    if (!host()->permissions().HasPermission(ppapi::PERMISSION_DEV)) {
+      // IMPORTANT: Clear PP_FILEOPENFLAG_WRITE and PP_FILEOPENFLAG_APPEND so
+      // the plugin can't write and so bypass our quota checks.
+      flags_to_send =
+          open_flags_ & ~(PP_FILEOPENFLAG_WRITE | PP_FILEOPENFLAG_APPEND);
+    }
+    if (!AddFileToReplyContext(flags_to_send, &reply_context))
+      pp_error = PP_ERROR_FAILED;
+  }
+  reply_context.params.set_result(pp_error);
+  host()->SendReply(reply_context, PpapiPluginMsg_FileIO_OpenReply());
+  state_manager_.SetOperationFinished();
+}
+
+void PepperFileIOHost::ExecutePlatformWriteCallback(
+    ppapi::host::ReplyMessageContext reply_context,
+    base::PlatformFileError error_code,
+    int bytes_written) {
+  // On the plugin side, the callback expects a parameter with different meaning
+  // depends on whether is negative or not. It is the result here. We translate
+  // for the callback.
+  int32_t pp_error = ppapi::PlatformFileErrorToPepperError(error_code);
+  reply_context.params.set_result(ErrorOrByteNumber(pp_error, bytes_written));
+  host()->SendReply(reply_context, PpapiPluginMsg_FileIO_GeneralReply());
+  state_manager_.SetOperationFinished();
+}
+
+void PepperFileIOHost::GetRenderProcessHost(
+    base::Callback<void(RenderProcessHost*)> callback) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  if (render_process_host_) {
+    callback.Run(render_process_host_);
+  } else {
+    BrowserThread::PostTaskAndReplyWithResult(
+        BrowserThread::UI,
+        FROM_HERE,
+        base::Bind(&RenderProcessHost::FromID, render_process_id_),
+        base::Bind(&PepperFileIOHost::GotRenderProcessHost,
+                   weak_factory_.GetWeakPtr(),
+                   callback));
+  }
+}
+
+void PepperFileIOHost::GotRenderProcessHost(
+    base::Callback<void(RenderProcessHost*)> callback,
+    RenderProcessHost* host) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  render_process_host_ = host;
+  callback.Run(render_process_host_);
+}
+
+bool PepperFileIOHost::AddFileToReplyContext(
+    int32_t open_flags,
+    ppapi::host::ReplyMessageContext* reply_context) const {
+  base::ProcessId plugin_process_id =
+      base::GetProcId(browser_ppapi_host_->GetPluginProcessHandle());
+  if (!browser_ppapi_host_->external_plugin())
+    plugin_process_id = render_process_id_;
+  IPC::PlatformFileForTransit transit_file = BrokerGetFileHandleForProcess(
+      file_, plugin_process_id, false);
+  if (transit_file == IPC::InvalidPlatformFileForTransit())
+    return false;
+  ppapi::proxy::SerializedHandle file_handle;
+  file_handle.set_file_handle(transit_file, open_flags);
+  reply_context->params.AppendHandle(file_handle);
+  return true;
+}
+
+}  // namespace content